I've tried to create UML diagram with MSVS 2010 b2 today and I've faced a problem. After I added controls from toolbox (such as Class, Interface) I could not connect these items! So connecting controls have been disabled on the toolbox when I tried to drag it on working area.
How to connect UML controls?
thx
You can connect shapes as described here: How to: Edit a UML Model and Diagrams
Basically, click the connector in the Toolbox, the source shape, and then the target shape. You can also right-click the source shape, click Add, and then the connector you want.
If this does not work, please use the following steps to file a bug through Microsoft Connect: How to submit feedback on Microsoft Connect
You might also want to try the RC version, which has fixed many issues: Microsoft Visual Studio 2010 Ultimate RC